Grindstone dressing tool protection device

ABSTRACT

Grinding machine comprises rotatably mounted grindstone and rotatable grindstone dressing device having axis of rotation parallel to axis of grindstone. Protector shield is mounted between dressing tool and grindstone for protecting dressing tool at all times except during actual dressing operation of grindstone. Motivator moves protector shield into and out of alignment with dressing tool and grindstone so that dressing tool is protected by shield when shield is positioned between tool and grindstone.

United States Patent Gm 1 Feb. 13, 1973 GRINDSTONE DRESSING TOOL [56]References Cited PROTECTION DEVICE UNITED STATES PATENTS Inventor:Hiroshi Toyoda Koki 3,017,875 l/1962 Jones ..125 11 c1) Kabushiki Kaishaof 1,1-chome, 3,006,332 10/1961 Cooper 125/11 CD Asahimachi, Kariya,Aichi Prefectum, Japan Primary ExaminerHarold D. WhiteheadAttorney-Connolly & Hutz [22] Filed: March 31, 1971 21 Appl. No.:129,876 1 ABSTRACT Grinding machine comprises rotatably mountedgrindstone and rotatable grindstone dressing device having [30] ForelgnApplication Pnonty Data axis of rotation parallel to axis of grindstone.Protec- April 7, 1970 Japan ..45/29686 tor shield is mounted betweendressing tool and grindstone for protecting dressing tool at all timesexcept during actual dressing operation of grindstone. Motivator movesprotector shield into and out of [52] US. Cl ..125/11 R alignment withdressing tool and grindstone so that [5 l Il-ll. Cl. ..B24b 53/00dressing too] is protected by Shield when Shield is posi [58] FleldofSearch ..125/ ll C, ll CD, ll R tioned between tool and grindstone 3Claims, 3 Drawing Figures PATENTEUFEBIB I975 3,716,041

' SHEET 2 [IF 2 GRINDSTONE DRESSING TOOL PROTECTION DEVICE BACKGROUND OFTHE INVENTION The present invention relates to a dressing tool for agrindstone, and more particularly to a protection device for thedressing tool that shields the tool from the grindstone except during agrindstone dressing operation.

Most grinding machines include a dressing tool located very close to thegrindstone. As is well known, the dressing tool is moved into engagementwith the face of the grindstone during the dressing operation. After thedressing operation is completed the dressing tool is moved away from theface of the grindstone until the next dressing operation. Frequently,conditions are such that the grindstone breaks apart while itis'rotating. In many instances, the grindstone fragments are thrownunder significant centrifugal force and fly outwardly in all directions.These fragments often strike SUMMARY OF THE INVENTION Accordingly, it isan object of the present invention to provide a grinding tool protectiondevice which shields the dressing tool from flying grindstone fragmentswhich might otherwise damage the dressing tool.

In accordance with the present invention a device for dressing agrindstone comprises support structure with a grindstone rotatablymounted to the support structure. A dresser housing is fixed to thesupport structure, and a ram is supported by and slidably fitted to thedresser housing. The ram is moved toward and away from the grindstone,and a grindstone dressing tool is mounted at the end of the ram oppositethe grindstone for periodic dressing of the grindstone. A dressing toolprotector shield is mounted between the dressing tool and thegrindstone, and motivating structure is pro 'vided for moving the shieldinto and out of alignment with the dressing tool and the grindstone sothat the tool is protected by the shield when the shield is posi-.tioned between the tool and the grindstone. The motivating structure,for moving the protector shield into and out of alignment with thedressing tool and the grindstone preferably includes a drive shaftconnected to the shield and a motor for rotating the drive shaft tothereby move the shield. Also, the connection between the drive shaftand the protector shield preferably includes a shock absorber in theform of a leaf spring. Moreover, the dressing tool may be in the form ofa dressing roller with a motor for rotating the roller during a dressingoperation of the grindstone.

BRIEF DESCRIPTION OF THE DRAWING Novel features and advantages of thepresent invention in addition to those mentioned above will becomeapparent to those skilled in the art from a reading of the followingdetailed description in conjunction with the accompanying drawingwherein:

FIG. I is a longitudinal sectional view of a device for dressing agrindstone according to the present invention;

FIG. 2 is a sectional view taken along line 2-2 of FIG. I; and

FIG. 3 is an end elevation illustrating the dressing tool protectordevice of the present invention.

DETAILED DESCRIPTION OF THE INVENTION Referring in more particularity tothe drawing, FIG. 1 shows a grinder table 1 with a grindstone 17rotatably mounted to the table by a shaft (not shown). A dresser housing2 is rigidly fitted to the grinder table 1. A ram 3 is slidably fittedwithin the housing 2 and is prevented from rotating relative to thehousing by a pin 3a in the housing which fits within a longitudinal slot3b in the ram. Thus, the ram is only capable of axial movement withinthe dresser housing 2. The end of the ram 3 carries a support member 14upon which a diamond dressing roller 15 is rotatably mounted. Thedressing roller 15 is driven by a hydraulic motor 16 fixed to thesupport member 14.

The rear of the dresser housing 2 carries a casing 4. The casingsupports a feed shaft 6 having a feed screw 6a formed at the endthereof. The feed screw 6a meshes-with an internally threaded sleeve 7attached to the ram 3. As shown in FIG. 1, a cylinder block 5 is securedto the casing 4. The block 5 has a fast feed cylinder 8 with a piston 9therein for reciprocating the dressing roller 15 and thereby moving ittoward and away from the face of'thegrindstone 17. The piston isconnected to the ram 3 by the feed screw 6. The left face of the piston9, as viewed in FIG. 1, carries an extended shaft 6b'integrally formedon the shaft 6 which in turn carries an adjustable dog 37. Ports 8a, 8bare provided in the cylinder block 5 for motivating the piston 9. Also,the feed shaft 6 has a gear 10 that meshes with an intermediate gear 11which in turn meshes with another gear 12 secured to an infeed shaft 13connected to a conventional infeed motivating means (not shown).

The casing 4 also carries a cylinder block 35, as best illustrated inFIG. 2. A cylinder 18 is formed in the block and a piston 19 having rods20, 21 is fitted inside the cylinder 18 of the block 35. The threadedend portion 20a of the piston rod 20 carries dogs 30a, 30b while thepiston rod 21 has a rack 21a formed thereon. Ports 18a, 18b in the block35 are connected to a pressurized fluid supply source (not shown) formanipulating the piston 19.

A rotatable shaft 24 is positioned on the outside of the dresser housing2. The shaft is supported by bearings 25,25 and the axis of rotation ofthe shaft is substantially parallel to the axis of the feed shaft 6. Agear 22 is secured at one end of the rotating shaft 24. The gear 22meshes with the rack 21a on the piston rod 21. The other end of theshaft 24 is operably connected to a second shaft 23 by a coupling 26.The coupling has a longitudinal key groove 28 and'a key 27 mounted onthe rotating shaft 24 forms the axially slidably connection between thecoupling 26 and the shaft 24.

The drive shaft 23 is rotatably mounted by a bearing member 29integrally. formed on the side wall of the support member' 14 thatcarries the diamond dressing roller 15. As mentioned above, one end ofthe drive shaft 23 is secured to the coupling 26, and a stop screw 31provides the positive connection between the shaft 23 and the coupling.The other end of the shaft has a plate 32 fixed thereto. A shockabsorber in the form of a leaf spring 34 is secured to the plate 32 anda dressing tool protector shield 33 is secured to the leaf spring. Asshown in FIG. 1, the shield 33 is located between the diamond dressingroller and the grindstone 17. This is the position of the shield duringthe grinding operation. However, when the grinding tool is dressed, the

shield is first moved away from its position between the dressing tooland the grindstone.

The operation of the structure of the present invention is as follows.First, prior to the actual dressing operation of the grindstone fluidpressure is introduced into the port 18b of the cylinder 18. This causesthe piston 19 to move to the left, as viewed in FIG. 2. As the piston somoves, the gear 22 meshing with the rack 21a on the shaft 21 rotates andthereby causes the drive shaft 24 to rotate. As is clear, the rotatingshaft 24 causes the coupling 26 to rotate which in turn causes the driveshaft 23 to rotate in the same direction. The protector shield 33 beingconnected to the shaft 23 is thereby moved from the position shown inFIG. 3 to the secondary position shown in FIG. 3 in phantom outline.Next, the dog 30b associated with the piston rod actuates the limitswitch 36b to indicate that the shield 33 is positioned away from itsprotective position between the dressing roller 15 and the grindstone17.

Upon actuation of the limit switch 36b pressurized fluid is supplied tothe fast feed cylinder 8 via the inlet port 8a. This causes the piston 9to move to the right, as viewed in FIG. 1, which piston causes the shaft6, ram 3 and the coupling 26 to move relative to the rotatable shaft 24in an axial direction toward the grindstone l7. Ultimately, the piston 9reaches the end of its forward movement and stops. At this position thediamond dressing roller 15 at the end of the ram 3 is usually locateddirectly adjacent the outer peripheral face of the grindstone 17. Next,the infeed shaft 13 is rotated and this rotation is transmitted to theinfeed shaft 6 via the gearing 12, ll, 10. Rotation of the feed shaft 6causes the ram to move closer to the grindstone 17 whereby the diamonddressing roller 15 engages the peripheral face of the grindstone todress the grindstone. As explained above, the dresser roller 15 isrotated by the hydraulic motor 16 during the actual dressing operation.

After the grindstone is dressed to the desired degree, the roller 15 iswithdrawn by reverse rotation of the infeed shaft 13. The amount ofwithdrawal of the shaft 6 is slightly less than the amount of forwardmovement thereof whereby the dressing roller is accurately positionedfor the next dressing operation. At the same time, pressurized fluid isintroduced into the port 8b of the fast feed cylinder 8 to therebyfurther retract the ram 3 to its original starting position. The dog 37actuates the limit switch 38 which causes pressurized fluid to flow intothe cylinder 18 via the inlet port 180. The piston 19 then slides to theright, as viewed in FIG. 2, which causes the gear 22 to rotate in adirection opposite to its previous rotation. Rotation of the gear 22 istransmitted to the protector shield 33 via the shafts 23, 24.Ultimately, the shield 33 swings back to its protective position directlbetween the dressing roller 15 and the grindstone 17. his position isbest shown in FIG. 3.

Ultimately, limit switch 36a is actuated by the dog 30a on the-pistonrod 20 which confirms that the protector shield 33 is in its specifiedprotective position. The hydraulic motor 16 then stops and the grindingoperation with the grindstone 17 can then be resumed.

As mentioned above, the protector shield of the present inventionoperates to protect the expensive diamond dressing roller during actualgrinding of a workpiece with the grindstone 17. Often, the grindstone isbroken during the grinding operation and fragments fly away from thestone under great centrifugal force. The shield 33 protects the dressingroller from damage which might otherwise occur if the flying grindstonefragments were allowed to strike the roller.

In the claims:

1. In a device for dressing a grindstone comprising support structure, agrindstone rotatably mounted to the support structure, a dresser housingfixed to the support structure, a ram supported by and slidably fittedto the dresser housing, means for moving the ram toward and away fromthe grindstone, and a grindstone dressing tool rotatably mounted on theend of the ram opposite the grindstone for periodic dressing of thegrindstone, the improvement comprising a dressing tool protector shieldrotatably mounted on the ram between the dressing tool and thegrindstone, and means for moving the protector shield into and out ofalignment with the dressing tool and the grindstone including a driveshaft operably connected to the protector shield and motivating meansmounted on the dresser housing for rotating the drive shaft and therebyrotating the shield protector whereby the dressing tool is protected bythe shield when the shield is positioned between the tool and thegrindstone.

2. The combination of claim 1 in which the connection between the driveshaft and the protector shield includes shock absorber means.

3. The combination of claim 2 in which the shock absorber meanscomprises a leaf spring.

1. In a device for dressing a grindstone comprising support structure, a grindstone rotatably mounted to the support structure, a dresser housing fixed to the support structure, a ram suppoRted by and slidably fitted to the dresser housing, means for moving the ram toward and away from the grindstone, and a grindstone dressing tool rotatably mounted on the end of the ram opposite the grindstone for periodic dressing of the grindstone, the improvement comprising a dressing tool protector shield rotatably mounted on the ram between the dressing tool and the grindstone, and means for moving the protector shield into and out of alignment with the dressing tool and the grindstone including a drive shaft operably connected to the protector shield and motivating means mounted on the dresser housing for rotating the drive shaft and thereby rotating the shield protector whereby the dressing tool is protected by the shield when the shield is positioned between the tool and the grindstone.
 1. In a device for dressing a grindstone comprising support structure, a grindstone rotatably mounted to the support structure, a dresser housing fixed to the support structure, a ram suppoRted by and slidably fitted to the dresser housing, means for moving the ram toward and away from the grindstone, and a grindstone dressing tool rotatably mounted on the end of the ram opposite the grindstone for periodic dressing of the grindstone, the improvement comprising a dressing tool protector shield rotatably mounted on the ram between the dressing tool and the grindstone, and means for moving the protector shield into and out of alignment with the dressing tool and the grindstone including a drive shaft operably connected to the protector shield and motivating means mounted on the dresser housing for rotating the drive shaft and thereby rotating the shield protector whereby the dressing tool is protected by the shield when the shield is positioned between the tool and the grindstone.
 2. The combination of claim 1 in which the connection between the drive shaft and the protector shield includes shock absorber means. 